Abstract

The purpose of this guide is to detail phenological
stages in white spruce that can be observed with the
naked eye, specifically the apical bud break stages
occurring in the spring and apical bud formation
stages occurring at the end of the growing season.
Although six phenological stages were previously
identified in a characterization of apical bud break
in white spruce, the
morphological changes that occur in the buds were
not detailed. By contrast, in black spruce, seven bud
break stages were described in detail for the lateral
buds. The bud
break stages described in this guide for the apical
buds of white spruce are largely based on the bud
break stages previously described for black spruce.
The apical bud formation stages in white spruce
were defined by using the four phenological stages
previously described for black spruce and adding two significant intermediate
stages.